Undesirable side-effect

Side-effects are not caused by malfunction, deterioration or inadequate information, which separates them from incidents caused by device problems. Expected side-effects belong in the risk file and the instructions, and a rise in their frequency or severity can still call for trend reporting.

An ‘undesirable side-effect’ under the MDR should be understood as any unintended and unwanted medical manifestation in the human body, as a consequence of the normal use of a medical device. Undesirable side-effects are not the result of a malfunction, deterioration in the characteristics or performance of the medical device, or an inadequacy in the information supplied by the manufacturer.

MDCG 2023-3 Rev.2, Question 10